碼上歡樂
相關內容    簡體    繁體

Kubernetes之kubectl常用命令使用指南:2:故障排查

本文轉載自   查看原文   2017-07-17 23:41   13075 

kubectl是一個用於操作kubernetes集群的命令行接口,通過利用kubectl的各種命令可以實現各種功能,是在使用kubernetes中非常常用的工具。這里我們會通過一些簡單的實例來展現其中一些高頻命令的使用方法。 
更為重要的是這些命令使用的場景以及能夠解決什么樣的問題。上篇文章我們介紹了創建和刪除相關的幾條命令，這篇文章我們來看一下出現問題時最常用的另外九條命令。

常用命令

kubectl故障排查相關，本文將會簡單介紹一下如下命令

項番 命令 說明
No.1 version 顯示客戶端和服務器側版本信息
No.2 api-versions 以group/version的格式顯示服務器側所支持的API版本
No.3 explain 顯示資源文檔信息
No.4 get 取得確認對象信息列表
No.5 describe 取得確認對象的詳細信息
No.6 logs 取得pod中容器的log信息
No.7 exec 在容器中執行一條命令
No.8 cp 從容器考出或向容器考入文件
No.9 attach Attach到一個運行中的容器上

事前准備

kubectl version

version命令用於確認客戶端和服務器側的版本信息，不同的版本的情況變化可能很大，所以故障排除時首先也需要確認的是現場環境的版本信息。 
從下面可以清楚地看到，本文驗證時所使用的版本為1.5.2

[root@ku8-1 tmp]# kubectl version Client Version: version.Info{Major:"1", Minor:"5", GitVersion:"v1.5.2", GitCommit:"08e099554f3c31f6e6f07b448ab3ed78d0520507", GitTreeState:"clean", BuildDate:"2017-01-12T04:57:25Z", GoVersion:"go1.7.4", Compiler:"gc", Platform:"linux/amd64"} Server Version: version.Info{Major:"1", Minor:"5", GitVersion:"v1.5.2", GitCommit:"08e099554f3c31f6e6f07b448ab3ed78d0520507", GitTreeState:"clean", BuildDate:"2017-01-12T04:52:34Z", GoVersion:"go1.7.4", Compiler:"gc", Platform:"linux/amd64"} [root@ku8-1 tmp]#
  • 1
  • 2
  • 3
  • 4

集群構成

一主三從的Kubernetes集群

項番 類型 Hostname IP
No.1 Master ku8-1 192.168.32.131
No.1 Node ku8-2 192.168.32.132
No.1 Node ku8-3 192.168.32.133
No.1 Node ku8-4 192.168.32.134 
[root@ku8-1 tmp]# kubectl get nodes NAME STATUS AGE 192.168.32.132 Ready 12m 192.168.32.133 Ready 11m 192.168.32.134 Ready 11m [root@ku8-1 tmp]#
  • 1
  • 2
  • 3
  • 4
  • 5
  • 6

kubectl api-versions

使用api-versions命令可以列出當前版本的kubernetes的服務器端所支持的api版本信息。

[root@ku8-1 tmp]# kubectl api-versions apps/v1beta1 authentication.k8s.io/v1beta1 authorization.k8s.io/v1beta1 autoscaling/v1 batch/v1 certificates.k8s.io/v1alpha1 extensions/v1beta1 policy/v1beta1 rbac.authorization.k8s.io/v1alpha1 storage.k8s.io/v1beta1 v1 [root@ku8-1 tmp]#
  • 1
  • 2
  • 3
  • 4
  • 5
  • 6
  • 7
  • 8
  • 9
  • 10
  • 11
  • 12
  • 13

kubectl explain

使用kubectl explain可以和kubectl help一樣進行輔助的功能確認，使用它可以了解各個部分的說明和組成部分。比如如下可以看到對rc的說明，在故障排除時作用並不具有太大作用，到是可以多讀讀加深一下對各個部分的理解。

[root@ku8-1 ~]# kubectl explain rc DESCRIPTION: ReplicationController represents the configuration of a replication controller. FIELDS: apiVersion <string> APIVersion defines the versioned schema of this representation of an object. Servers should convert recognized schemas to the latest internal value, and may reject unrecognized values. More info: http://releases.k8s.io/HEAD/docs/devel/api-conventions.md#resources kind <string> Kind is a string value representing the REST resource this object represents. Servers may infer this from the endpoint the client submits requests to. Cannot be updated. In CamelCase. More info: http://releases.k8s.io/HEAD/docs/devel/api-conventions.md#types-kinds metadata <Object> If the Labels of a ReplicationController are empty, they are defaulted to be the same as the Pod(s) that the replication controller manages. Standard object's metadata. More info: http://releases.k8s.io/HEAD/docs/devel/api-conventions.md#metadata spec <Object> Spec defines the specification of the desired behavior of the replication controller. More info: http://releases.k8s.io/HEAD/docs/devel/api-conventions.md#spec-and-status status <Object> Status is the most recently observed status of the replication controller. This data may be out of date by some window of time. Populated by the system. Read-only. More info: http://releases.k8s.io/HEAD/docs/devel/api-conventions.md#spec-and-status [root@ku8-1 ~]#
  • 1
  • 2
  • 3
  • 4
  • 5
  • 6
  • 7
  • 8
  • 9
  • 10
  • 11
  • 12
  • 13
  • 14
  • 15
  • 16
  • 17
  • 18
  • 19
  • 20
  • 21
  • 22
  • 23
  • 24
  • 25
  • 26
  • 27
  • 28
  • 29
  • 30
  • 31
  • 32
  • 33
  • 34
  • 35
  • 36

explain命令能夠確認的信息類別

其所能支持的類別如下：

類別
clusters (僅對federation apiservers有效)
componentstatuses (縮寫 cs)
configmaps (縮寫 cm)
daemonsets (縮寫 ds)
deployments (縮寫 deploy)
endpoints (縮寫 ep)
events (縮寫 ev)
horizontalpodautoscalers (縮寫 hpa)
ingresses (縮寫 ing)
jobs
limitranges (縮寫 limits)
namespaces (縮寫 ns)
networkpolicies
nodes (縮寫 no)
persistentvolumeclaims (縮寫 pvc)
persistentvolumes (縮寫 pv)
pods (縮寫 po)
podsecuritypolicies (縮寫 psp)
podtemplates
replicasets (縮寫 rs)
replicationcontrollers (縮寫 rc)
resourcequotas (縮寫 quota)
secrets
serviceaccounts (縮寫 sa)
services (縮寫 svc)
statefulsets
storageclasses
thirdpartyresources

事前准備

剩下的一些命令需要事前作一些准備，我們還是用上篇文章所用的yaml文件創建mysql和sonarqube的Deployment和pod。

yaml文件准備

[root@ku8-1 tmp]# ls yamls mysql.yaml sonar.yaml [root@ku8-1 tmp]# cat yamls/mysql.yaml --- kind: Deployment apiVersion: extensions/v1beta1 metadata: name: mysql spec: replicas: 1 template: metadata: labels: name: mysql spec: containers: - name: mysql image: 192.168.32.131:5000/mysql:5.7.16 ports: - containerPort: 3306 protocol: TCP env: - name: MYSQL_ROOT_PASSWORD value: "hello123" [root@ku8-1 tmp]# cat yamls/sonar.yaml --- kind: Deployment apiVersion: extensions/v1beta1 metadata: name: sonarqube spec: replicas: 1 template: metadata: labels: name: sonarqube spec: containers: - name: sonarqube image: 192.168.32.131:5000/sonarqube:5.6.5 ports: - containerPort: 9000 protocol: TCP [root@ku8-1 tmp]#
  • 1
  • 2
  • 3
  • 4
  • 5
  • 6
  • 7
  • 8
  • 9
  • 10
  • 11
  • 12
  • 13
  • 14
  • 15
  • 16
  • 17
  • 18
  • 19
  • 20
  • 21
  • 22
  • 23
  • 24
  • 25
  • 26
  • 27
  • 28
  • 29
  • 30
  • 31
  • 32
  • 33
  • 34
  • 35
  • 36
  • 37
  • 38
  • 39
  • 40
  • 41
  • 42
  • 43
  • 44

啟動

[root@ku8-1 tmp]# kubectl create -f yamls/ deployment "mysql" created deployment "sonarqube" created [root@ku8-1 tmp]#
  • 1
  • 2
  • 3
  • 4

kubectl get

使用get命令確認所創建出來的pod和deployment的信息

確認pod

可以看到創建出來的pod的所有信息,也可以使用Kubectl get po進行確認

[root@ku8-1 tmp]# kubectl get pods NAME READY STATUS RESTARTS AGE mysql-478535978-1dnm2 1/1 Running 0 34s sonarqube-3574384362-m7mdq 1/1 Running 0 34s [root@ku8-1 tmp]#
  • 1
  • 2
  • 3
  • 4
  • 5

確認deployment

可以看到創建出來的deployment的所有信息

[root@ku8-1 tmp]# kubectl get deployments NAME DESIRED CURRENT UP-TO-DATE AVAILABLE AGE mysql 1 1 1 1 41s sonarqube 1 1 1 1 41s [root@ku8-1 tmp]#
  • 1
  • 2
  • 3
  • 4
  • 5

如果希望得到更加詳細一點的信息，可以加上-o wide參數,比如對pods可以看到此pod在哪個node上運行，此pod的集群IP是多少也被一並顯示了

[root@ku8-1 tmp]# kubectl get pods -o wide NAME READY STATUS RESTARTS AGE IP NODE mysql-478535978-1dnm2 1/1 Running 0 2m 172.200.44.2 192.168.32.133 sonarqube-3574384362-m7mdq 1/1 Running 0 2m 172.200.59.2 192.168.32.134 [root@ku8-1 tmp]#
  • 1
  • 2
  • 3
  • 4
  • 5

確認node信息

顯示node的信息

[root@ku8-1 tmp]# kubectl get nodes -o wide NAME STATUS AGE EXTERNAL-IP 192.168.32.132 Ready 6h <none> 192.168.32.133 Ready 6h <none> 192.168.32.134 Ready 6h <none> [root@ku8-1 tmp]#
  • 1
  • 2
  • 3
  • 4
  • 5
  • 6

確認namespace信息

列出所有的namespace

[root@ku8-1 tmp]# kubectl get namespaces NAME STATUS AGE default Active 6h kube-system Active 6h [root@ku8-1 tmp]#
  • 1
  • 2
  • 3
  • 4
  • 5

get命令能夠確認的信息類別

使用node/pod/event/namespaces等結合起來，能夠獲取集群基本信息和狀況, 其所能支持的類別如下：

類別
clusters (僅對federation apiservers有效)
componentstatuses (縮寫 cs)
configmaps (縮寫 cm)
daemonsets (縮寫 ds)
deployments (縮寫 deploy)
endpoints (縮寫 ep)
events (縮寫 ev)
horizontalpodautoscalers (縮寫 hpa)
ingresses (縮寫 ing)
jobs
limitranges (縮寫 limits)
namespaces (縮寫 ns)
networkpolicies
nodes (縮寫 no)
persistentvolumeclaims (縮寫 pvc)
persistentvolumes (縮寫 pv)
pods (縮寫 po)
podsecuritypolicies (縮寫 psp)
podtemplates
replicasets (縮寫 rs)
replicationcontrollers (縮寫 rc)
resourcequotas (縮寫 quota)
secrets
serviceaccounts (縮寫 sa)
services (縮寫 svc)
statefulsets
storageclasses
thirdpartyresources

kubectl describe

確認node詳細信息

一般使用get命令取得node信息，然后使用describe確認詳細信息。

[root@ku8-1 tmp]# kubectl get nodes NAME STATUS AGE 192.168.32.132 Ready 6h 192.168.32.133 Ready 6h 192.168.32.134 Ready 6h [root@ku8-1 tmp]# kubectl describe node 192.168.32.132 Name: 192.168.32.132 Role: Labels: beta.kubernetes.io/arch=amd64 beta.kubernetes.io/os=linux kubernetes.io/hostname=192.168.32.132 Taints: <none> CreationTimestamp: Wed, 28 Jun 2017 23:06:22 -0400 Phase: Conditions: Type Status LastHeartbeatTime LastTransitionTime Reason Message ---- ------ ----------------- ------------------ ------ ------- OutOfDisk False Thu, 29 Jun 2017 05:52:07 -0400 Wed, 28 Jun 2017 23:06:22 -0400 KubeletHasSufficientDisk kubelet has sufficient disk space available MemoryPressure False Thu, 29 Jun 2017 05:52:07 -0400 Wed, 28 Jun 2017 23:06:22 -0400 KubeletHasSufficientMemory kubelet has sufficient memory available DiskPressure False Thu, 29 Jun 2017 05:52:07 -0400 Wed, 28 Jun 2017 23:06:22 -0400 KubeletHasNoDiskPressure kubelet has no disk pressure Ready True Thu, 29 Jun 2017 05:52:07 -0400 Wed, 28 Jun 2017 23:06:34 -0400 KubeletReady kubelet is posting ready status Addresses: 192.168.32.132,192.168.32.132,192.168.32.132 Capacity: alpha.kubernetes.io/nvidia-gpu: 0 cpu: 1 memory: 2032128Ki pods: 110 Allocatable: alpha.kubernetes.io/nvidia-gpu: 0 cpu: 1 memory: 2032128Ki pods: 110 System Info: Machine ID: 22718f24279240be9fe0c469187f901a System UUID: 9F584D56-F5B3-FAB8-3985-938D67451312 Boot ID: fe3b2606-37ee-4b07-8de2-438fe29bf765 Kernel Version: 3.10.0-514.el7.x86_64 OS Image: CentOS Linux 7 (Core) Operating System: linux Architecture: amd64 Container Runtime Version: docker://1.13.1 Kubelet Version: v1.5.2 Kube-Proxy Version: v1.5.2 ExternalID: 192.168.32.132 Non-terminated Pods: (0 in total) Namespace Name CPU Requests CPU Limits Memory Requests Memory Limits --------- ---- ------------ ---------- --------------- ------------- Allocated resources: (Total limits may be over 100 percent, i.e., overcommitted. CPU Requests CPU Limits Memory Requests Memory Limits ------------ ---------- --------------- ------------- 0 (0%) 0 (0%) 0 (0%) 0 (0%) No events. [root@ku8-1 tmp]#
  • 1
  • 2
  • 3
  • 4
  • 5
  • 6
  • 7
  • 8
  • 9
  • 10
  • 11
  • 12
  • 13
  • 14
  • 15
  • 16
  • 17
  • 18
  • 19
  • 20
  • 21
  • 22
  • 23
  • 24
  • 25
  • 26
  • 27
  • 28
  • 29
  • 30
  • 31
  • 32
  • 33
  • 34
  • 35
  • 36
  • 37
  • 38
  • 39
  • 40
  • 41
  • 42
  • 43
  • 44
  • 45
  • 46
  • 47
  • 48
  • 49
  • 50
  • 51
  • 52
  • 53
  • 54

確認pod

確認某一pod詳細信息

[root@ku8-1 tmp]# kubectl describe pod mysql-478535978-1dnm2 Name: mysql-478535978-1dnm2 Namespace: default Node: 192.168.32.133/192.168.32.133 Start Time: Thu, 29 Jun 2017 05:04:21 -0400 Labels: name=mysql pod-template-hash=478535978 Status: Running IP: 172.200.44.2 Controllers: ReplicaSet/mysql-478535978 Containers: mysql: Container ID: docker://47ef1495e86f4b69414789e81081fa55b837dafe9e47944894e7cb3733700410 Image: 192.168.32.131:5000/mysql:5.7.16 Image ID: docker-pullable://192.168.32.131:5000/mysql@sha256:410b279f6827492da7a355135e6e9125849f62eeca76429974a534f021852b58 Port: 3306/TCP State: Running Started: Thu, 29 Jun 2017 05:04:22 -0400 Ready: True Restart Count: 0 Volume Mounts: /var/run/secrets/kubernetes.io/serviceaccount from default-token-dzs1w (ro) Environment Variables: MYSQL_ROOT_PASSWORD: hello123 Conditions: Type Status Initialized True Ready True PodScheduled True Volumes: default-token-dzs1w: Type: Secret (a volume populated by a Secret) SecretName: default-token-dzs1w QoS Class: BestEffort Tolerations: <none> No events. [root@ku8-1 tmp]#
  • 1
  • 2
  • 3
  • 4
  • 5
  • 6
  • 7
  • 8
  • 9
  • 10
  • 11
  • 12
  • 13
  • 14
  • 15
  • 16
  • 17
  • 18
  • 19
  • 20
  • 21
  • 22
  • 23
  • 24
  • 25
  • 26
  • 27
  • 28
  • 29
  • 30
  • 31
  • 32
  • 33
  • 34
  • 35
  • 36
  • 37

確認deployment詳細信息

確認某一deployment的詳細信息

[root@ku8-1 tmp]# kubectl get deployment NAME DESIRED CURRENT UP-TO-DATE AVAILABLE AGE mysql 1 1 1 1 1h sonarqube 1 1 1 1 1h [root@ku8-1 tmp]# kubectl describe deployment mysql Name: mysql Namespace: default CreationTimestamp: Thu, 29 Jun 2017 05:04:21 -0400 Labels: name=mysql Selector: name=mysql Replicas: 1 updated | 1 total | 1 available | 0 unavailable StrategyType: RollingUpdate MinReadySeconds: 0 RollingUpdateStrategy: 1 max unavailable, 1 max surge Conditions: Type Status Reason ---- ------ ------ Available True MinimumReplicasAvailable OldReplicaSets: <none> NewReplicaSet: mysql-478535978 (1/1 replicas created) No events. [root@ku8-1 tmp]#
  • 1
  • 2
  • 3
  • 4
  • 5
  • 6
  • 7
  • 8
  • 9
  • 10
  • 11
  • 12
  • 13
  • 14
  • 15
  • 16
  • 17
  • 18
  • 19
  • 20
  • 21
  • 22

describe命令能夠確認的信息

describe命令所能支持的類別如下：

類別
clusters (僅對federation apiservers有效)
componentstatuses (縮寫 cs)
configmaps (縮寫 cm)
daemonsets (縮寫 ds)
deployments (縮寫 deploy)
endpoints (縮寫 ep)
events (縮寫 ev)
horizontalpodautoscalers (縮寫 hpa)
ingresses (縮寫 ing)
jobs
limitranges (縮寫 limits)
namespaces (縮寫 ns)
networkpolicies
nodes (縮寫 no)
persistentvolumeclaims (縮寫 pvc)
persistentvolumes (縮寫 pv)
pods (縮寫 po)
podsecuritypolicies (縮寫 psp)
podtemplates
replicasets (縮寫 rs)
replicationcontrollers (縮寫 rc)
resourcequotas (縮寫 quota)
secrets
serviceaccounts (縮寫 sa)
services (縮寫 svc)
statefulsets
storageclasses
thirdpartyresources

kubectl logs

類似於docker logs，使用kubectl logs能夠取出pod中鏡像的log，也是故障排除時候的重要信息

[root@ku8-1 tmp]# kubectl get pods NAME READY STATUS RESTARTS AGE mysql-478535978-1dnm2 1/1 Running 0 1h sonarqube-3574384362-m7mdq 1/1 Running 0 1h [root@ku8-1 tmp]# kubectl logs mysql-478535978-1dnm2 Initializing database ... 2017-06-29T09:04:37.081939Z 0 [Note] Event Scheduler: Loaded 0 events 2017-06-29T09:04:37.082097Z 0 [Note] mysqld: ready for connections. Version: '5.7.16' socket: '/var/run/mysqld/mysqld.sock' port: 3306 MySQL Community Server (GPL) [root@ku8-1 tmp]#
  • 1
  • 2
  • 3
  • 4
  • 5
  • 6
  • 7
  • 8
  • 9
  • 10
  • 11

kubectl exec

exec命令用於到容器中執行一條命令，比如下述命令用於到mysql的鏡像中執行hostname命令

[root@ku8-1 tmp]# kubectl get pods NAME READY STATUS RESTARTS AGE mysql-478535978-1dnm2 1/1 Running 0 1h sonarqube-3574384362-m7mdq 1/1 Running 0 1h [root@ku8-1 tmp]# kubectl exec mysql-478535978-1dnm2 hostname mysql-478535978-1dnm2 [root@ku8-1 tmp]#
  • 1
  • 2
  • 3
  • 4
  • 5
  • 6
  • 7

更為常用的方式則是登陸到pod中，在有條件的時候，進行故障發生時的現場確認，這種方式是最為直接有效和快速，但是對權限要求也較多。

[root@ku8-1 tmp]# kubectl exec -it mysql-478535978-1dnm2 sh # hostname mysql-478535978-1dnm2 #
  • 1
  • 2
  • 3
  • 4

kubectl cp

用於pod和外部的文件交換，比如如下示例了如何在進行內外文件交換。

在pod中創建一個文件message.log

[root@ku8-1 tmp]# kubectl exec -it mysql-478535978-1dnm2 sh # pwd / # cd /tmp # echo "this is a message from `hostname`" >message.log # cat message.log this is a message from mysql-478535978-1dnm2 # exit [root@ku8-1 tmp]#
  • 1
  • 2
  • 3
  • 4
  • 5
  • 6
  • 7
  • 8
  • 9

拷貝出來並確認

[root@ku8-1 tmp]# kubectl cp mysql-478535978-1dnm2:/tmp/message.log message.log
tar: Removing leading `/' from member names [root@ku8-1 tmp]# cat message.log this is a message from mysql-478535978-1dnm2 [root@ku8-1 tmp]#
  • 1
  • 2
  • 3
  • 4
  • 5

更改message.log並拷貝回pod

[root@ku8-1 tmp]# echo "information added in `hostname`" >>message.log [root@ku8-1 tmp]# cat message.log this is a message from mysql-478535978-1dnm2 information added in ku8-1 [root@ku8-1 tmp]# kubectl cp message.log mysql-478535978-1dnm2:/tmp/message.log [root@ku8-1 tmp]#
  • 1
  • 2
  • 3
  • 4
  • 5
  • 6

確認更改后的信息

[root@ku8-1 tmp]# kubectl exec mysql-478535978-1dnm2 cat /tmp/message.log this is a message from mysql-478535978-1dnm2 information added in ku8-1 [root@ku8-1 tmp]#
  • 1
  • 2
  • 3
  • 4

kubectl attach

類似於docker attach的功能，用於取得實時的類似於kubectl logs的信息

[root@ku8-1 tmp]# kubectl get pods NAME READY STATUS RESTARTS AGE mysql-478535978-1dnm2 1/1 Running 0 1h sonarqube-3574384362-m7mdq 1/1 Running 0 1h [root@ku8-1 tmp]# kubectl attach sonarqube-3574384362-m7mdq If you don't see a command prompt, try pressing enter.
  • 1
  • 2
  • 3
  • 4
  • 5
  • 6
  • 7

kubectl cluster-info

使用cluster-info和cluster-info dump也能取出一些信息，尤其是你需要看整體的全部信息的時候一條命令一條命令的執行不如kubectl cluster-info dump來的快一些

[root@ku8-1 tmp]# kubectl cluster-info Kubernetes master is running at http://localhost:8080 To further debug and diagnose cluster problems, use 'kubectl cluster-info dump'. [root@ku8-1 tmp]#
  • 1
  • 2
  • 3
  • 4
  • 5

總結

這篇文章中介紹了九個kubectl的常用命令，利用它們在故障確認和排查中非常有效。

 
 

http://www.woaipu.com/shops/zuzhuan/61406
http://www.znds.com/tv-967956-1-1.html
http://www.znds.com/tv-967958-1-1.html

http://www.woaipu.com/shops/zuzhuan/61406
http://www.znds.com/tv-967956-1-1.html
http://www.znds.com/tv-967958-1-1.html


免責聲明！

本站轉載的文章為個人學習借鑒使用，本站對版權不負任何法律責任。如果侵犯了您的隱私權益，請聯系本站郵箱yoyou2525@163.com刪除。



猜您在找 Kubernetes之kubectl常用命令 Kubernetes 學習筆記（三）：kubectl 常用命令及插件 kubectl常用命令 kubectl 常用命令 kubectl常用命令（一） kubectl 常用命令 kubectl常用命令 kubectl使用方法及常用命令小結 kubectl 常用命令總結 kubectl 常用命令總結
 
粵ICP備18138465號   © 2018-2025 CODEPRJ.COM